[tz] Unable to compile Antarctica/Macquarie

[Paul Eggert]

Wow, that's *really* backwards compatible: it changes
each of three files to do the right thing if it is
used with older versions of the other two.

I tried it on a 64-bit platform (Fedora 17 x86-64)
and it worked just fine, so I pushed it to github as
<https://github.com/eggert/tz/commit/fada9b7b05339d848f6fcacb4a1c4fd51b49ec7d>.
This includes one minor further change of tabs to spaces to
get a source-code line to fit in 80 characters.

Thanks!